Duchy of Saint Sava

Duchy of Saint Sava (Latin: Ducatus Sancti Sabae,Serbo-Croatian: Hercegovina Svetog Save) was a late medieval South Slavicstate which existed amid the Ottomanconquest of the Balkans. It was ruled by Stjepan Vukčić and his son Vladislav, of the Kosača noble family, and included parts of modern-day Bosnia & Herzegovina, Croatia, Montenegro and Serbia.

HISTORY
On 15 February 1444, Stephen signed a treaty with Alfonso V, King of Aragon and Naples, becoming his vassal in exchange for the king's help against Stjepan's enemies, namely King Stephen Thomas of Bosnia, Duke Ivaniš Pavlović and the Republic of Venice. In the same treaty Stjepan promised to pay regular tribute to Alfonso instead of his tribute to the Ottoman sultan, which he had done up until then.

In a document sent to Holy Roman Emperor Frederick III on 20 January 1448, Stephen Vukčić Kosača styled himself "Vojvoda (duke, herzog) of Saint Sava", "Lord of Hum and the Coast", and "Grand Duke", and forced the Bosnian king to recognize him as such.The title "Duke of Saint Sava" had considerable public relations value, because Sava's relics, which were located in Mileševa, were considered miracle-working by people of all Christian faiths in the region.This significantly improved relations between Stjepan and the Serbian Despot Đurađ Branković, as they formed an alliance the same year and conquered Višegrad and Srebrnica from the Bosnian crown.

In 1451 Stjepan attacked Dubrovnik, and laid siege to the city. He had earlier been made a Ragusan nobleman and, consequently, the Ragusan government now proclaimed him a traitor.[9] A reward of 15,000 ducats, a palace in Dubrovnik worth 2,000 ducats, and an annual income of 300 ducats was offered to anyone who would kill him, along with the promise of hereditary Ragusan nobility which also helped hold this promise to whoever did the deed.Stjepan was so scared by the threat that he finally raised the siege.[9]

Stjepan Vukčić died in 1466, and was succeeded by his eldest son Vladislav Hercegović. In 1482 he was overpowered by Ottoman forces led by Stjepan Vukčić's youngest son, Hersekli Ahmed Pasha, who converted to Islam prior to that. In the Ottoman Empire, Herzegovina was organized as a province (sanjak) within the state (pashaluk) of Bosnia.

Stjepan founded the Serbian OrthodoxZagrađe Monastery near his realm's seat in Herceg Novi, modern-day Montenegro, and the Savina Monastery, also near Herceg Novi.